Cased cartridge

ABSTRACT

A lightweight &#39;&#39;&#39;&#39;piggyback&#39;&#39;&#39;&#39; propellant container is integrally formed with a warhead for travel to a target, the propellant container being imperforate and deformable upon ignition to effect substantially instantaneous exhaust of the products of combustion for launching the warhead and its propellant container from a breech of a firearm barrel.

niie tet 1 Olsen States 1 Jan. 28, 1.975

1 CASED CARTRIDGE [75] Inventor: Charles R. Olsen, West Chester, Pa.

[73] Assignee: Colt Industries, Operating Corp., Hartford, Conn.

[22] Filedf Oct. 19, 1972 [21] Appl. No.: 299,003

[52] US. Cl 102/38, 102/493, 102/93 [51] Int. Cl. F42b 9/02 [58] Fieldof Search 102/38, 40, 43, 44, 45, 102/497, 49.3, 93

[56] References Cited UNITED STATES PATENTS 1,191,357 7/1916 Snyder102/497 1,602,037 10/1926 Mixsell 1,812,010 6/1931 McBride 102/4972,856,856 10/1958 Michael 102/93 2,996,012 8/1961 Butler 102/933,687,079 8/1972 Scollins.. 102/93 X 3,724,377 3/1973 Birkigt [OZ/49.7

Primary Examiner-Benjamin A. Borchelt Assistant Examiner-H. J. TudorAttorney, Agent, or FirmPrutzman, Hayes, Kalb & Chilton I [57] ABSTRACTA lightweight piggyback" propellant container is integrally formed witha warhead for travel to a target, the propellant container beingimperforate and deformable upon ignition to effect substantiallyinstantaneous exhaust of the products of combustion for launching thewarhead and its propellant container from a breech of a firearm barrel.

7 Claims, 5 Drawing Figures PAINTED- 3,862,599

sum 20F 2 FIG. 5 17/ f CASED CARTRIDGE This invention generally relatesto projectiles and particularly to a cased cartridge of a so-calledmonopressure type which is propelled from a firearm barrel as anintegral mass.

A primary object of this invention is to provide a new and improvedcased cartridge having a warhead and integral lightweight propellantcontainer at its breech end forming a sealed propellant compartmentparticularly suited to be. launched from a firearm barrel such as alaunch tube and carried to a target with the warhead.

A further object of this invention is to provide such a cartridge whicheliminates any need for extraction of empty cartridge cases. i

A still further object is to provide such a cartridge which virtuallyprecludes pre-ignition from radiant energy and effectively prevents suchspontaneous preignition of a cartridge upon its being advanced by a feedmechanism to battery position.

Another object of this invention is to provide such a cartridge whereinits propellant container is formsustaining but deformable upon firing toexpand in a controlled manner to effect substantially instantaneousexhaust of the products of propellant combustion for launching thewarhead together with its propellant container from a fire-arm barrel.

A still further object of this invention is to provide such a casedcartridge exhibiting the additional advantageous characteristic ofeffective obturation.

A still further object of this invention is to provide a cased cartridgeof the type described having additional advantages of minimizing theweight and cost of conventional metallic cases, simplifying theassociated weapon system by eliminating any requirement for manual orautomatic extraction or ejection after firing while obtaining thebenefits of conventional cased cartridges in preserving the mechanicalintegrity of the round to readily permit conventional storage andhandling and at the same time being highly resistant to adverse effectsof moisture, mold, etc. under widely varying and sometimes demandingenvironmental conditions.

Still another object of this invention is to provide such a casedcartridge which is quickly and easily manufactured and assembled.

Other objects will be in part obvious and in part pointed out in moredetail hereinafter.

A better understanding of the objects, advantages, features, propertiesand relationships of the invention will be obtained from the followingdetailed description and accompanying drawings which set forth certainillustrative embodiments and are indicative of the ways in which theprinciple of the invention is employed.

In the drawings:

FIG. 1 is a sideview of a cartridge, partly broken away and partly insection, incorporating this inventron;

FIG. 2 is a partial side view of an end portion of a cartridge, partlybroken away and partly in section, incorporating another embodiment ofthis invention and showing a portion of a firearm barrel from which thecartridge is launched;

FIG. 3 is an end view of the projectile of FIG. 2 shown prior to itsbeing fired;

FIG. 4 is a longitudinal section view of a cartridge incorporating stillanother embodiment of this invention; and

FIG. 5 is a partial side view, partly broken away and partly in section,showing an end portion of a cartridge incorporating another embodimentof this invention.

Referring to the drawings in detail, a cased cartridge 10 having agenerally cylindrical warhead or projectile is illustrated in FIG. 1having a nose portion 14 which would be directed toward a target and abreech portion 16 carrying a propellant container 18. Encased within thecontainer 18 is a combustible propellant 20 of conventional type whichupon ignition serves to launch the cartridge 10 toward a target. Thepropellant container 18 is preferably formed from a cup-shapedlightweight form-sustaining but deformable material such as aluminum,e.g., and includes a generally annular side wall 22 which in FIG. 1 isintegral with an end wall 24 and a forward wall 26 fixed to a rear ofthe projectile 12 by any suitable means such as an igniter 28 secured toa threaded projection 30 extending coaxially from the rear of projectile12.

The igniter 28 is a hollow cylindrical component having radial passages32 communicating a central opening 34 of the igniter 28 with an internalpropellant compartment 36 defined within propellant container 18. Whilea suitable electric primer of conventional type may be provided, thepreferred embodiment is shown having a typical percussion primer 38mounted in an extreme rear portion of the central opening 34 in theigniter 28 whereby the rear end of the primer 38 is exposed for impactignition by a conventional percussion element of a firearm such as alaunch tube, not shown, from which the cartridge 10 is to be launched.The radial passages 32 in the igniter 28 are preferably closed off bycombustible tape such as at 40 and a cardboard wad 42, e.g., may bemounted in a forward portion of the central opening 34 whereby asuitable ignition mix 44 is effectively sealed within the igniter 28.

By virtue of the above described construction, the

end wall 24 of the propellant container 18 may be suitably crimped inposition as at 46 wherein a deformable elastomeric tube 47 is fittedaround a crimped annular central portion of end wall 24 and releasablyretained in position about the adjacent outer periphery of igniter 28.Such construction ensures that the internal propellant compartment 36 issealed off against entry of moisture, dirt and other undesirablecontaminants and thereby prevents deterioration which effects burningnot only of the ignition mix 44 within the igniter 28 but also thepropellant 20 within the compartment 36 upon firing of primer 38.

To effect a controlled rupture of the enclosed sealed propellantcompartment 36 in accordance with this invention, the side and end walls22 and 24 of the propellant container 18 are suitably dimensioned andconfigured such that pressure build-up to a predetermined optimum levelwithin compartment 36 upon ignition of the propellant 20 causes thenormally sealed and crimped annular central portion of end wall 24 at 46to be blown open as indicated by broken lines at 48 to substantiallyinstantaneously exhaust the products of propelant combustion forlaunching projectile 12 and its propellant container 18 in its entiretyfrom the barrel or launch tube.

To effectively obturate a closed breech end of a firearm barrel, anobturator band 50 is shown secured to the breech end of the cartridge 10such that upon being driven up the taper of the projectile boat-tail bygas pressure during propellant combustion, the obturator band 50 will beforced into sealing engagement with the internal wall of the firearmbarrel. If desired, the obturator band 50 may be formed of a toughimpactresistant form-sustaining plastic such as nylon and may bemechanically snap-fit over adjacent knurled portions such as at 52 atthe rear of the projectile l2 and the container side wall 22 to providea rough surface for the obturator band 50 to grasp and to provide adriving torque to rotate the projectile with a spin velocity. Thefirearm barrel may be provided with conventional lands 54 and grooves56, such as in barrel 58 illustrated in FIG. 2, thereby ensuring that ahigh spin velocity is imparted to the cartridge about its majorlongitudinal axis upon launch. To minimize turbulent drag during flight,controlled fracture of the band 50 may be intentionally effected toprovide band discard shortly beyond the firearm muzzle under centrifugalforce while the cartridge 10 is spinning at high velocity. In thisregard, the obturator band 50 if desired may be scored by premoldingsuch as at 60 to fracture and effect discard of the obturator band 50after'launch for improved aerodynamic characteristics, e.g., whereby therearwardly tapered configuration of the propellant container 18 providesa boat-tail effect.

It should be also noted that the igniter 28 is formed with an extractorgroove 62 which facilitates removal of the cartridge 10 from the barrelfor any reason before firing or in the event of misfire, etc. Moreover,for improved sealing within the propellant compartment 36 and theigniter 28 to preserve the integrity of the propellant charge andignition mix 44 during storage, e.g., theigniter is preferably formed ofa suitable metal to further preclude the entrance of any unwantedmoisture, etc., into the igniter passages and the propellantcompartment.

In FIG. 2 there is illustrated a modified cased cartridge 110 having aprojectile 112 and attached propellant container 118 defining acompartment 136 for receiving a combustible propellant 120 all of whichare substantially identical in construction and characteristics as thatdescribed in connection with the embodiment of FIG. 1. The igniter 128has a generally tubular body with communicating passageways 132, 132extending generally radially from a central opening 134 which maycontain a suitable ignition mix 144 and which is closed at its extremerear end portion by a primer 138. The forward end of the central opening134 15 closed and, if desired, may be provided with a suitable tracermix, not shown, since the igniter 128 is shown affixed to a rear of theprojectile 112 and it carried with it during launch from barrel 58. Theleading end of obturator band 150 is snap-fitted over side wall 122 ofpropellant container 118 which in turn is crimped into position as at170 about groove 171 in a breech end of projectile 112. The end wall 124at the breech end of projectile 112 is releasably crimped between tube147 and igniter 128 as described in FIG. 1 to provide a desired sealagainst foreign matter while at the same time subject to rupture tosubstantially instantaneously vent the gaseous byproducts of propellantcombustion at the juncture of container 118 and igniter 128. As bestseen in FIG. 3, the propellant compartment end wall 124 is formed in arose-crimp arrangement radiating outwardly from the coaxially disposedingiter 128. As a further illustration of the type of modificationpermitted with this cased cartridge 110, the obturator band 150 isformed with a suitable extractor cannelure 172. In addition, the entirecontainer side wall 122 and end wall assembly together with theobturator band 150 may be fractured off, if desired, for improvedaerodynamic characteristics in flight after the projectile 112 has beenlaunched from the firearm barrel 58.

If desired, cased cartridge of this invention may be provided with amaximum outer diameter less than the minimum internal diameter'offirearm barrel 58 such that the cartridge 110 may be utilized as amortar, for example, to be dropped into a mortar tube such as that ofbarrel 58 to detonate the primer 138 causing heat and shock ignition ofthe projectile propellant to drive projectile 112 with its propellantcontainer 110 out of the mortar tube upon ignition of the base charge120 and rupture of the propellant container 118 to exert thrust to thecartridge 110 from the breech end of the mortar tube. Localizedexpansion of the obturator band effects positive physical engagementwith the lands 54' and grooves 56 of barrel 58 to not only seal off thebreech end of the barrel 58 but to also ensure that a spin velocity willbe imparted to the projectile 112 for maximizing accuracy of theprojectile trajectory.

Still another embodiment of this invention is shown in FIG. 4 whereinside wall 222 of propellant container 218 is integrally formed by arearwardly extending portion of projectile 212 surrounding a cavity inthe breech end portion 216 of the cartridge 210 for receiving a basecharge 220. A closure disc 224 serves as an end wall for sealingpropellant compartment 236 and, in the illustrated embodiment, is shownsecured in position by an igniter 228 threadably secured within an axialopening 280 of reduced size formed in the rear of projectile 212 incommunication with its propellant compartment 236. Internal axialopening 234 within igniter 128 and its communicating radial passages232, 232 are substantially the same as previously described, as isprimer 238 located at the rear of the igniter 228. Ignition of mix 244within the igniter opening 234 causes the burning of tape 240, whichnormally closes off communicating passages 232, 232 and the subsequentcombustion of propellant 220 within main propellant compartment 236.Combustion of propellant 220 will build up gas pressure, distort andfracture the end wall seal at the outer periphery of disc 224 where itengages the projectile side wall 222 to substantially instantaneouslyrelease combustion gases into a breech of a firearm barrel to launchcased cartridge210. For completeness, it is also noted that cartridge210 of FIG. 4 is shown with an obturator band 250 integrally formed onthe projectile body. Also, as previously described, breech portion 216of the cartridge 210 is preferably tapered for improved aerodynamiccharacteristics.

FIG. 5 shows another embodiment of this invention wherein combustiblepropellant 320 is encased in a short tubular propellant container 318,formed, e.g., of aluminum, and comprising the rear of projectile 312.

If desired, a tracer assembly 390 may be mounted within main propellantcompartment 336 upon fitting the tracer assembly 390 onto an inner endportion of igniter 328. A suitable tracer mix 391 is disposed withintracer assembly sleeves 392 having open ends positioned adjacent anannular end portion of container 318. A closure disc 324 is placed overigniter 328 and expanded into a groove 394 in the propellant container318. Thereafter, the terminal end of igniter 328 is rolled over to forma retaining lip 395 for the closure disc 324 and to seal the propellantcompartment 336. Upon firing, the closure disc 324 partially opens aboutits outer periphery at its juncture with the propellant container 318,allowing the propellant gas to escape substantially instantaneously intothe chamber of the launch tube or firearm barrel, not shown, to launchthe cased cartridge 310. The burning of the propellant 320 causesignition of the tracer mix 391 which escapes past the outer periphery ofthe distorted disc 324. While the tracer assembly 390 is shown in theembodiment of FIG. 5, obviously such an assembly may be optionaldepending on the requirements to which the cartridge 310 is to beapplied.

From the foregoing description, it will be appreciated that a casedcartridge of the type described incorporates a construction particularlysuited to provide a water'proof, weather-proof round which preserves themechanical integrity of the ammunition during storage, handling,ramming, etc. while also providing for convenient extraction forunloading chambered cartridges should such extraction be desired.Normally, no ejection and no extraction is encountered upon firing of around thereby significantly simplifying the operating components of theassociated weapon. Moreover, such advantages have been achieved in thedesign of this invention while providing the additional advantages ofelimination of weight and cost of a conventional metallic case inaddition to eliminating any undesired residue in a breech end of theweapon for launching the cartridge of this invention, since the entirecartridge including its lightweight piggyback propellant compartment iscarried with the projectile upon launch. The aluminum case additionallyserves to reflect radiant heat and accordingly minimizes any chance ofpremature ignition of the cartridges being advanced into batteryposition.

As will be apparent to persons skilled in the art, variousmodifications, adaptations and variations of the foregoing specificdisclosure can be made without departing from the teachings of thepresent invention.

I claim:

l. A cased cartridge for firing as an integral unit from a breech of afirearm barrel comprising a projectile, a propellant container carriedon a rear portion of said projectile, said propellant container havingan annular side wall and an end wall on a breech end of said projectile,said side and end walls being formed of imperforate form sustainingnoncombustible material jointly defining and normally sealing anenclosed propellant containing compartment, said projectile having a tapered rear side wall configuration providing a tapered boat-tail on therear of said projectile, an obturator band mounted in surroundingrelation to said tapered boat-tail of said projectile to effectobturation of propellant gases upon being driven up the projectileboattail by'the gaseous products of combustion, and a combustilblepropellant received within said compartment, said propellant containerbeing deformable such that pressure buildup to a predetermined levelwithin said compartment upon ignition of said propellant causescontrolled rupture of the enclosed sealed compartment and effectssubstantially instantaneous exhaust of products of combustion forlaunching said cartridge in its entirety from the firearm barrel.

2. The cartridge of claim 1 in combination with the firearm barrelhaving rifling lands and grooves, and wherein expansion of the gaseousproducts of combustion effects driving movement of said obturator bandalong said tapered boat-tail of said projectile into positive physicalengagement with the rifling lands and grooves ofthe firearm barrel toform a seal and provide a driving torque to impart a spin velocity tosaid cartridge upon its being launched from the firearm barrel in adirection along the cartridge spin axis.

3. The combination of claim 2 wherein said obturator band is formed of afrangible material and is detachable after launch during flight.

4. The cartridge of claim 2 wherein said obturator band is formed of atough impact resistant, formsustaining plastic.

5. The cartridge of claim 4 wherein said obturator band and saidprojectile are mutually dimensioned and configured to permit snap-onconnection of said obturator band in an assembled unit providingpositive mechanical engagement between said obturator band and saidprojectile.

6. The cartridge of claim 2 wherein the projectile includes a knurledportion in contact engagement with the obturator band about theprojectile to impart said driving torque.

7. The cartridge of claim 1 wherein said propellant container side wallis detachably mounted on said tapered boat-tail on the rear of saidprojectile to be launched with said projectile as an integral unit whilepermitting discard of at least a portion of said propellant containerafter launch during flight.

1. A cased cartridge for firing as an integral unit from a breech of afirearm barrel comprising a projectile, a propellant container carriedon a rear portion of said projectile, said propellant container havingan annular side wall and an end wall on a breech end of said projectile,said side and end walls being formed of imperforate form sustainingnoncombustible material jointly defining and normally sealing anenclosed propellant containing compartment, said projectile having atapered rear side wall configuration providing a tapered boat-tail onthe rear of said projectile, an obturator band mounted in surroundingrelation to said tapered boat-tail of said projectile to effectobturation of propellant gases upon being driven up the projectileboat-tail by the gaseous products of combustion, and a combustilblepropellant received within said compartment, said propellant containerbeing deformable such that pressure build-up to a predetermined levelwithin said compartment upon ignition of said propellant causescontrolled rupture of the enclosed sealed compartment and effectssubstantially instantaneous exhaust of products of combustion forlaunching said cartridge in its entirety from the firearm barrel.
 2. Thecartridge of claim 1 in combination with the firearm barrel havingrifling lands and grooves, and wherein expansion of the gaseous productsof combustion effects driving movement of said obturator band along saidtapered boat-tail of said projectile into positive physical engagementwith the rifling lands and grooves of the firearm barrel to form a sealand provide a driving torque to impart a spin velocity to said cartridgeupon its being launched from the firearm barrel in a direction along thecartridge spin axis.
 3. The combination of claim 2 wherein saidobturator band is formed of a frangible material and is detachable afterlaunch during flight.
 4. The cartridge of claim 2 wherein said obturatorband is formed of a tough impact resistant, form-sustaining plastic. 5.The cartridge of claim 4 wherein said obturator band and said projectileare mutually dimensioned and configured to permit snap-on connection ofsaid obturator band in an assembled unit providing positive mechanicalengagement between said obturator band and said projectile.
 6. Thecartridge of claim 2 wherein the projectile includes a knurled portionin contact engagement with the obturator band about the projectile toimpart said driving torque.
 7. The cartridge of claim 1 wherein saidpropellant container side wall is detachably mounted on said taperedboat-tail on the rear of said projectile to be launched with saidprojectile as an integral unit while permitting discard of at least aportion of said propellant container after launch during flight.